How do I add a GPG key to my Bitbucket account?

From within Bitbucket Server, go to your account by clicking your profile picture in the upper-right, and select Manage account.

The profile picture is in the lower-left corner, and selecting "Bitbucket settings" which appears to be the closest choice to "Manage account" in the list, there is nothing about GPG keys, only SSH keys, and GPG key adding is not in there.